grammar → 又
TSUMUGU · TBCL 2 (est.) · 語法
grammar point · tier 1 · 又 recurrence — it happened once more (realized repetition)
· yòu
adv — marks an event as a repeat of one that already happened; placed before the verb.

字源 FORM what the parts do

又 is a right hand drawn whole — three fingers and a wrist. The hand's own senses left for 右 and 有; the bare graph stayed on for again. Set before the verb, it tags the action as a return of one already seen.

故事 STORY a scene to remember it by

A door already swung shut once; now the same hand pushes it open a second time. The earlier opening is done, and this push repeats it.
字源自撰記憶法
框 · Frame
[subj] 又 [verb (+ 了)]
觸 · Trigger
Something just happened that has happened before, and you mark this as the repeat.
序 · The move
1confirm the event is a return of one already realized, not one still plannedhas it actually happened this time? If still intended, reach for 再 instead.
2drop 又 in front of the verbis 又 before the verb, never after it?
3let 了 close the realized action where it fitsdoes the sentence read as a completed recurrence?
例 · Examples
1heagain (a repeat of what already happened)忘了forgot寫功課do homework
He forgot to do his homework again.
界 · Boundary
又 marks a repeat that has already happened (he forgot again); 再 marks a repeat not yet done (do it once more). 又 looks back at a realized event; 再 looks ahead to an intended one.
又 repeats the same event over time (it happened, now it happens again); 也 adds a second subject or item alongside the first (this one too).
using 又 for an unrealized future repeat: 明天我又去 → 明天我再去
placing 又 after the verb: 他忘了又寫功課 → 他又忘了寫功課
using 再 for something already repeated: 他再忘了寫功課 → 他又忘了寫功課
English 'again' is one word for both the past repeat and the planned one; learners use 又 where 再 is needed for future or imperative repetition.